Science Quarter 2- Matter - DepEd Tambayan

CO_Q2_Science 9_ Module 2

Science

Quarter 2- Matter Module 2: Chemical Bonding:

Properties of Compounds

9

Science – Grade 9

Alternative Delivery Mode

Quarter 2: Matter - Module 2: Chemical Bonding: Properties of Compounds

First Edition, 2020

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9

Science Quarter 2- Matter

Module 2: Chemical Bonding:

Properties of Compounds

Introductory Message

This Self-Learning Module (SLM) is prepared so that you, our dear learners,

can continue your studies and learn while at home. Activities, questions, directions,

exercises, and discussions are carefully stated for you to understand each lesson.

Each SLM is composed of different parts. Each part shall guide you step-by-

step as you discover and understand the lesson prepared for you.

Pre-tests are provided to measure your prior knowledge on lessons in each

SLM. This will tell you if you need to proceed on completing this module or if you

need to ask your facilitator or your teacher’s assistance for better understanding of

the lesson. At the end of each module, you need to answer the post-test to self-check

your learning. Answer keys are provided for each activity and test. We trust that you

will be honest in using these.

In addition to the material in the main text, Notes to the Teacher are also

provided to our facilitators and parents for strategies and reminders on how they can

best help you on your home-based learning.

Please use this module with care. Do not put unnecessary marks on any part

of this SLM. Use a separate sheet of paper in answering the exercises and tests. And

read the instructions carefully before performing each task.

If you have any questions in using this SLM or any difficulty in answering the

tasks in this module, do not hesitate to consult your teacher or facilitator.

Thank you.

1


What I Need to Know

This module is designed and written with you in mind. It is here to help you

master Chemical Bonding: Properties of Compounds. The scope of this module

permits it to be used in many different learning situations. The language used

recognizes the diverse vocabulary level of students. The lessons are arranged to follow

the standard sequence of the course, but the order in which you read them can be

changed to correspond with the textbook you are now using.

The module focuses on achieving this learning competency:

Recognize different types of compounds (ionic or covalent) based on their

properties such as melting point, hardness, polarity, and electrical and thermal

conductivity. (S9MT-IIb-14)

After going through this module, you are expected to:

- identify and describe ionic and covalent compounds based on their

chemical formula and chemical names;

- enumerate and discuss different physical properties of ionic and covalent;

- distinguish ionic from covalent compound based on their physical properties;

and

- cite a natural phenomenon that uses different physical properties of ionic and

covalent compound (ex. Snowflakes, voltaic cells).

2


What I Know

Choose the letter of the best answer. Write your answer on a separate sheet of

paper.

1. The figure below represents the arrangement of particles in a substance. What

kind of substance is this?

A. Ionic compound

B. Metallic compound

C. Covalent compound

D. None of these

2. Which is a property of ionic compound?

A. soft and flexible

B. crystal lattice structure

C. liquid or gaseous state at room temperature

D. does not conduct electricity both in solid and melted form

3. Which is NOT a property of covalent compound?

A. It has low melting point

B. It exists in a stable crystalline structure.

C. It does not exhibit any electrical conductivity.

D. It is usually solid at normal temperature and pressure.

4. Which gives the best explanation of why a solid ionic compound DOES NOT

conduct electricity?

A. Solid ionic compounds do not have ions.

B. Solid ionic compounds are not soluble in water.

C. Solid ionic compounds have ions which are free to move.

D. Solid ionic compounds have ions, but these ions are not free to move.

5. Which substance conducts electricity when dissolved in water?

A. gasoline C. sugar

B. paraffin wax D. monosodium glutamate

6. Which of the following statements BEST explains the high solubility of sodium

chloride (NaCl) in water?

A. The ions are free to move.

B. There are positive and negative ions present in the substance.

C. Sodium chloride break apart into molecules, not an individual atom

when dissolve in water.

D. The positive and negative ions are attracted to different regions of the

polar water molecules.

3


7. Which of the following substances DO NOT exist in solid, liquid, or gas at room

temperature and normal atmospheric pressure?

I. gasoline III. salt II. snowflakes IV. water

A. A. I only B. II only C. III only D. III and IV only

8. Why do ionic compounds tend to be less flammable than covalent

compounds?

A. Ionic compounds are poor conductor of heat.

B. Ionic compounds do not have carbon and hydrogen atoms that react

when heated with oxygen gas.

C. Ionic compounds contain atoms that can react to form carbon dioxide

and water when heated with oxygen gas.

D. None of these

9. Why do ionic compounds conduct electricity when dissolved in water, but most covalent compounds do not?

A. Covalent compounds have lower melting point than ionic compounds. B. Covalent compounds are weakly bonded while ionic compounds are

strongly bonded. C. Covalent compounds do not dissolve in water since they are composed

of nonpolar molecules.

D. Covalent compounds dissolve into molecules, while ionic compounds dissolve into ions that conduct charge.

10. Snowflake is an example of compound that begins to form when an extremely

cold-water droplet freezes into a pollen or dust particle in the sky. Which is

TRUE about a snowflake?

A. Its chemical formula is the same as water.

B. Its structure is the same as the crystalline lattice of an ionic compound.

C. It is formed due to the transfer of electrons from two oxygen atoms to a

hydrogen atom.

D. It is formed when a raindrop freezes due to a very low temperature in

the atmosphere.

11. Why are some snow crystals big and complicated, but others are small and

simple looking? Because…

A. they differ in composition

B. some have ionic bonding, while others have covalent bonding

C. they differ in temperature and humidity of the cloud where they are

formed

D. the big ones are made up of saltwater while the small ones are made

up of fresh water.

4


12. The table below shows the result for electrical conductivity test of PbB𝑟2,

C10H8 and NaCl. Based on the results, what can you conclude about the three

substances tested?

State of

Compound

Lead (II)

bromide

(PbB𝑟2)

Naphthalene

(C10H8)

Sodium

chloride (NaCl)

Solid Light bulb does

not light up.

Light bulb does

not light up.

Light bulb does

not light up.

Aqueous

solution

Bulb lights up. Light bulb does

not light up.

Bulb lights up.

For item no. 13-14, refer to the figure below:

13. Which of the following is/are TRUE about voltaic cells as shown in the

diagram below?

A. I only C. I and II only

B. II only D. II and III only

A. PbB, C10H8 and NaCl are all ionic compounds.

B. PbB and C10H8 are covalent while NaCl is ionic.

C. C10H8 is covalent while PbB and NaCl are ionic.

D. PbB is an ionic compound while C10H8 and NaCl are covalent

compounds.

I. The reaction that takes place in it is reversible.

II. They have two conductive electrodes, a positive and negative electrode.

III. It is a device that produces electric current from energy released by

spontaneous reduction-oxidation reaction.

5


14. Which of the following shows the correct analogies using the information you

can get from the diagram?

I. anode-reduction: cathode oxidation

II. anode-oxidation: cathode reduction

III. positive electrode – anode: negative electrode - cathode

IV. positive electrode – cathode: negative electrode – anode

A. II only C. I and III only

B. IV only D. II and IV only

15. When humans sweat, we lose ions necessary for bodily functions; to

replenish them, we consume more ions, often in the form of an electrolyte

solution. In a sports drink, which compound is NOT considered as

electrolytes?

A. glucose C. potassium

B. sodium D. magnesium

6


Lesson

1 Chemical Bonding:

Properties of Compounds In the previous module, you have learned how the development of atomic models

like the Quantum Mechanical Model of the atom lead to the description of the

behavior of electrons within atoms. In this module, you will focus on how the different

types of compounds (ionic or covalent) can be recognized based on their properties

such as melting point, hardness, polarity, and electrical and thermal conductivity.

Here are some key questions for you to ponder after finishing this module:

1. How will you identify and describe ionic and covalent compound based on

their chemical formula and chemical name?

2. What are the different physical properties of ionic and covalent compounds?

3. How will you distinguish ionic from covalent compound based on their

physical properties?

4. What are the different natural phenomena that uses different properties of

ionic and covalent compound?

What’s In

The modern periodic table organizes elements in such a way that information about the elements and their properties are easier to understand and remember. For

example, the vertical column of the periodic table is called group, elements in the

same group share common properties. Classify the elements from the box below according to the group where they belong to complete the list of representative

elements. Use the chemical symbol of the element in answering. Write your answer on a separate sheet of paper.

Lead Helium Barium

Boron Oxygen Aluminum

Argon Chlorine Potassium Radon Nitrogen Magnesium

Sodium Hydrogen Phosphorous

7


Figure 1: Periodic Table of the Representative Elements

What’s New

Getting to Know Chemical Compounds Most elements bond with other elements to form chemical compounds. The

table below shows the list of commonly used chemical compounds. Identify the name of elements included in the given compound and determine whether the elements

are metal or non-metal. Answer for number 1 item is provided as an example. Write your answer on a separate sheet of paper.

Compounds Name of Elements

Involved

Types of Elements

1. Water (𝐻2𝑂) Hydrogen Oxygen

Nonmetal Nonmetal

2. Sugar (𝐶12𝐻22𝑂11 )

3. Potassium chloride (KCl)

4. Carbon Dioxide (CO2)

5. Sodium Chloride (NaCl)

Guide Questions:

1. How do compounds form?

2. What does a compound contain?

8


What is It

Let’s Bond with Ionic and Covalent Compounds Compounds play a big part in our everyday life, like for example, you can find

compounds present in food, air, cleaning chemicals, and literally in every object that

you can see or touch. Compounds are made up of elements that are chemically

bonded by electrostatic forces. Compounds can be classified as ionic or covalent. An

ionic compound is formed when metal (cation) transfers its valence electron/s to a

nonmetal (anion). The covalent compound is formed when nonmetals share their

valence electrons with another nonmetal. The figure below shows an illustration on

how each element transfer or share their valence electrons to attain stability.

Figure 2: Formation of Ionic and Covalent Compounds

Identifying and Describing Compounds through its Chemical Formula and Chemical Name Ionic and covalent compounds can be identified and described through their

chemical formula and name by observing the types of elements involved in a

compound. In chemistry, the chemical formula is a symbolic expression signifying

the number of atoms present in a molecular substance. We determine the type of

atom by referring to its chemical symbol. The number of atoms is determined by

the subscript attached to the symbol. On the other hand, chemical name shows

the name of each element involved in a compound. For example, carbon dioxide,

the chemical formula is written as C𝑂2. This means that this is an example of a

covalent compound, since the elements involved are nonmetals, namely, one carbon

atom and two oxygen atoms. Moreover, sodium chloride, which chemical formula

is written as NaCl is an example of an ionic compound. Since the elements involved

in a compound are sodium (Na) a metal and chlorine (Cl) a nonmetal. Take a look

at your answer in the table of compounds in the “What’s New” part of this module.

Which among the given compounds do you think can be classified as ionic and

covalent compounds based on their chemical formula and name?

9


Understanding the Different Properties of Compounds Ionic and covalent compounds have different physical properties that will help

distinguish them.

1. At normal atmospheric pressure and temperature, covalent compounds may

exist in solid, liquid, or a gas, while ionic compounds exist only as crystalline

solids.

The reason for this is, in covalent compounds, electrons are shared and no

full ionic charges are formed, which makes; the molecules in this compound not

strongly attracted to one another compared to ionic compounds. Thus, covalent

molecules move freely and tend to exist as liquid or gas at room temperature like

alcohol, which is widely used as a disinfectant, fuel, and as a main component of

alcoholic beverages.

Most ionic compounds do not actually exist as molecules; instead, the ions

are arranged in an alternating positive and negative ion bonded together in a

matrix. As a result, the ions are held rigidly together in their crystal lattice

structure, and that is why they are solid under normal atmospheric pressure and

temperature, like for example sodium chloride (NaCl), which is commonly used for

flavoring and preserving foods.

2. Ionic compounds generally have higher melting and boiling points while

covalent compounds have lower melting and boiling points.

Ionic compounds have high melting and boiling point because it takes a lot of

thermal energy for ions (charged atoms) in the crystal to separate them apart from

each other. On the other hand, covalent compounds have low melting and boiling

point because of the weak force of attraction between molecules. As a result, a

small amount of thermal energy can separate them.

Mara is preparing a lunch for her

family. While gathering all the ingredients for

her recipe, she is a bit confused between the

two identical canisters. One canister contains

salt (NaCl) and the other contains sugar ( ).

Both contents are white powder solid in

appearance at room temperature. Without

tasting the sample compounds in the

canister, how do you know if a compound is

salt (ionic) or sugar (covalent)?

Which is which?

Is it salt or sugar?

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3. Ionic compounds are hard and brittle, while covalent compounds are soft and

flexible.

Crystal lattices are among the factors that affect the hardness and brittleness

of compounds. This refers to the symmetrical three- dimensional arrangement of

atoms inside a crystal. The crystal lattices of ionic compounds are hard and not

easily scratched, however, it is brittle, which can lead changes to its shape or size.

In contrast, covalent compounds have molecules that are weakly attracted to each

other and are easily displaced.

Source: ccsearch.creativecommons.org/photos/

4. Ionic compounds have high polarity, while covalent compounds have low

polarity.

Polarity, in a compound, results in the distribution of electrical charge over

the atoms joined by a chemical bond. In a chemical bond, polarity arises from the

relative electronegativities of the elements. Electronegativity refers to the ability

of an atom to attract electrons toward itself in a chemical bond.

To determine the polarity of compounds, we simply determine the

electronegativity difference (EN) of a compound by subtracting the

electronegativity value of the elements involved in a compound. If the difference

in EN values between the metallic element and non-metallic elements is greater

than 1.9 the compound is considered as ionic in character. Covalent compound

may result in polar or nonpolar bond. Polar covalent bond results when the EN

difference of two non-metallic elements is equal to 0.5 and lower than 1.9. On the

other hand, nonpolar covalent bond results when the EN difference of non-

metallic elements is lower than 0.5. Two identical non-metallic elements

(diatomic molecules) always produce nonpolar covalent bond like nitrogen gas

(𝑁2), oxygen gas (𝑂2), and hydrogen gas (𝐻2).

Figure 3: Crystal Lattices of Sodium Chloride (NaCl)

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Example:

Compound Electronegativity

(EN) Value

Electronegativity

(EN) Difference

Polarity

1. Sodium

Chloride (NaCl)

Sodium

Chlorine

0.9

3.0

4.0 – 0.9 = 2.1

Ionic

2. Water (𝐻2O)

Hydrogen

Oxygen

2.1

3.5

3.5 -2.1= 1.4

Polar

covalent

3. Hydrogen gas (𝐻2)

Hydrogen

Hydrogen

2.1

2.1

2.1 – 2.1= 0

Nonpolar

covalent

5. Ionic compounds are usually soluble in water, while covalent compounds

tend to be less soluble in water.

Solubility is the ability of a substance that may exist in solid, liquid, or gas

form, referred to as the solute, to dissolve in solvent. Many ionic compounds are

highly soluble in water because water molecules, a polar solvent attract each of

the ions of an ionic compound and pull the ions away from one another. However,

ionic compounds are less soluble in solvents that contain a common ion. On the

other hand, some covalent compounds are not soluble in water: they do not

dissolve well in water. Compounds that have similar properties (particularly

polarity), tend to dissolve in each other. This concept is often expressed as “Like

dissolves like” but for substances with unlike polarities, like water and oil, where

water is polar and oil is nonpolar, these two substances are insoluble with each

other.

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6. Ionic compounds tend to be less flammable than covalent compounds.

Flammability refers to the ability of a chemical substance to burn causing fire.

Combustion happens when substances containing carbon and hydrogen reacted

with oxygen gas and it will form carbon dioxide (C𝑂2) and water (𝐻2 𝑂). For

example, organic compounds which are mostly found together in covalent

compounds burn because they contain carbon and hydrogen. As a result, more

covalent compounds tend to be more flammable than ionic compounds. However,

not all covalent compounds burn. For instance, water, though a covalent, has

molecule which is bonded with a polar covalent—that is why it is hard to start fire

with it.

Liquefied Petroleum Gas (LPG) is an example of covalent compound that

contain flammable mixture of hydrocarbon (hydrogen and carbon) gases. It is

usually used as fuel in cooking equipment, heating appliances, and vehicles. The

flammability property of this compound require all the liquefied petroleum gas

(LPG) industry participants to observe the minimum safety standards in the

transportation and distribution of the petroleum product in cylinders under the

mandated order of the Department of Energy (DOE), stated in their department

circular (DC) 2014-01-0001 or the “The LPG Industry Rules”.

7. Ionic compounds conduct heat and electricity compared to covalent

compounds.

The conductivity of a substance refers to its ability to transmit heat and

electricity. In a chemical bond, ionic compounds are generally considered a good

conductor of electricity when dissolved or in an aqueous solution. This is because

of the presence of mobile ions (solid electrolytes) in ionic compound that can

transfer electrical charge. Ionic compounds are also considered as good conductor

of heat because the ions are all next to each other, making it possible for energy to

be transferred efficiently from one place to another.

Covalent compounds, on the other hand, are considered as good insulators of

both electricity and heat. This is the reason why that there are no mobile charged

particles and electrons are shared by atoms in a covalent bond. Moreover, covalent

compounds have molecules that are not as tightly held to each other compared to

ions in an ionic compound. As a result of this, heat does not travel well, making

heat transfer less efficient.

Take note, these are only general properties, and there are always exceptions to

every rule.

Natural Phenomena that Uses Different Properties of Ionic and

Covalent Compounds

A. Frozen Fractals of Snowflakes

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Have you been dreaming of a white Christmas here in the Philippines, wherein

you can enjoy wearing your jackets while having a cup of hot chocolate over a

fireplace? Do you think it is possible for us Filipinos to witness having snow in a

yuletide season?

The Philippines is considered a tropical country, wherein according to PAGASA

(Philippine Astronomical Geophysical Atmospheric Space Administration), we

experience high relative humidity or moisture content of the atmosphere. Varying

between 71 percent in March and 85 percent in September, high humidity levels are

attributed to the high temperature and the bodies of water surrounding the

archipelago. Back in 2017, there were reports of hailstones, or ice pieces, each about

half an inch in diameter, falling over parts of Quezon City and Alabang. However,

hailstone, which refers to a frozen form of precipitation, is different from the snow.

Hailstone usually forms during a thunderstorm when upward moving air prevents ice

particles from falling from the atmosphere, making it suspended in the air as

supercooled water which freeze into the balls of ice.

In contrast, snow refers to small, soft, white pieces of ice. Snow is formed when

the temperature is low and there is moisture in the atmosphere in the form of tiny ice

crystals in clouds that stick together to become snowflakes. These snowflakes are

three- dimensional pattern with six-sided symmetry. Each molecule that joins the

snowflakes reflects the internal order of the crystal’s water molecules until eventually,

we can see its macroscopic six-sided shape. The chemical formula of snowflakes is

the same as water molecules. Therefore, the intermolecular force found in snowflakes

are a covalent bond. The hexagonal sides of snowflakes are the results of two

hydrogen atoms and one oxygen atom that form “bent” molecular shapes. This is a

result of the hydrogen bond that forms a dipole at the end of an oxygen atom. This

enables the hydrogen side to be positively charged and the oxygen side to be

negatively charged.

Figure 4: Molecular Structure of Snowflakes

Image from: ccsearch.creativecommons.org/search

14


B. Chemical Reactions as a Source of Power

One of the priorities of the researchers nowadays is to explore the usage of

chemical reactions to produce electricity. Understanding electrochemistry which

refers to the study of chemical process that causes the movement of electrons to

produce electricity, would greatly help reduce environmental problem that is

caused by burning coals.

Galvanic cell which is known as voltaic cell is a type of electrochemical cell

that uses chemical reaction to produce electric current, specifically an oxidation

reduction reaction. A battery that powers your gadgets like cellphone is an example

of voltaic cell.

The diagram below illustrates different parts and functions of voltaic cell.

Figure 5: Basic Set-up of Voltaic Cell

In order to generate a flow of electric charge, a strip of metal: zinc (Zn) and

copper (Cu) is placed in an aqueous solution containing the same metal, namely the

Zinc sulfate (ZnS𝑂42+) and copper sulfate (CuS𝑂4

2+) solution. A piece of wire is hooked

to connect a strip of zinc and copper metals, which causes the electrons, to move

within the wire. Zinc, which has a weaker pull for electrons, loses electron, which goes

through the wire which makes copper that has a strong pull for electron, gain

electrons. After the zinc ions turns into Z𝑛2+, it is no longer a part of a solid zinc metal

instead it becomes metal ions that dissolves in a solution (ZnS𝑂42+). On the other hand,

when copper gained two electrons it becomes a neutral atom, that can no longer

dissolve in the solution, instead it become a part of a solid copper metal.

15


In terms of chemical process, moving electrons create electricity, and flow from

a piece of zinc that serve as an anode, site of oxidation to a piece of copper, which is

the cathode, the site of reduction. These two reactions involve two half reaction of

oxidation and reduction. The voltaic cells also include a salt bridge that balance the

charges and allows the ions to flow from one half cell to another. In addition, a

voltmeter is used to measure potential difference between two half cells.

Activity 1: Out with the Old, In with the New Study the figures below that illustrate how ionic and covalent compound are

formed and answer the guide questions that follow. Write your answer on a separate

sheet of paper.

What’s More

Figure A: Formation of Sodium chloride (NaCl).

Figure B: Formation of water (𝐻2O).

Guide Questions:

1. What are the types of elements involved in the formation of the sodium chloride

(NaCl) and water (𝐻2O)?

2. How do sodium chloride (NaCl) and water (𝐻2O) form?

3. What leads to the transfer or sharing of valence electron between elements in a compound?

4. What type of compound is sodium chloride (NaCl) and water (𝐻2O)?

16


5. How will you identify and describe ionic and covalent compounds based on how

they are formed?

Activity 2: Know My Identity through My Chemical Formula

Study the list of compounds and its chemical formula below. Complete the table by identifying the correct chemical formula and classifying the type of compound for

each item. Write your answer on a separate sheet of paper.

Chemical Formula

𝐻2 𝐻2𝑂 NaCl

𝑁2 CO 𝑃𝐻3

HF MgC𝑙2 KI

KF 𝐵𝐻3 A𝑙2𝑂3

S𝑂2 HCl 𝐶12𝐻22𝑂11

Chemical Name Chemical

Formula

Ionic/Covalent

1. Water

2. Borane

3. Phosphine

4. Hydrogen gas

5. Nitrogen gas

6. Table sugar

7. Sulfur dioxide

8.Sodium chloride

9.Aluminum oxide

10.Carbon monoxide

11.Hydrogen fluoride

12.Potassium iodide

13.Hydrogen chloride

14. Potassium fluoride

15.Magnesium chloride

Guide Question:

● How will you describe and identify ionic and covalent compounds based on their

chemical name and formula?

17


Activity 3: Who Got the Power?

Study the four experimental set-ups below testing the electrical conductivity of

salt and sugar. Record your observation on the table. Write your answer on a separate sheet of paper.

Table 1: Electrical Conductivity of Salt and Sugar

Guide Questions:

1. Which among the sample materials conduct electricity when dissolved in water?

2. Explain why salt can conduct electricity when dissolved in water but not in its

solid state.

3. Why does sugar cannot conduct electricity in both solid and in a solution?

4. What type of compounds are sugar and salt?

5. What type of compound can conduct electricity?

Activity 4: Investigating Ionic and Covalent Profile

Imagine yourself as a young Filipino chemist in a laboratory. One of your

assistants conducted a series of experiments using the different compounds as

samples. Inefficiently, your assistant labelled the samples using uppercase letters

without having a list of the compound’s names assigned to each other. Use the data

Sample

Physical State of Sample

Materials (solid/liquid)

Electrical

Conductivity Yes/No

A. Salt Granules

B. Sugar Granules

C. Salt Dissolved in Water

D. Sugar Dissolved in Water

A Salt

Granules

B Sugar

Granules

C Salt Dissolved

in Water

D Sugar

Dissolved in

Water

18


given in Table No.1 to identify the given samples. Complete Table No.2 to show the

chemical name and classification of the samples. Write your answers on a separate

sheet of paper.

Table 1: Different Properties of the Samples

Sample Description Melting Point

(℃)

Boiling Point

(℃)

Solubility in Water

A

An odorless, colorless gas at room

temperature. Also known as dry ice in solid state

-77

-78.46

Soluble

B

An odorless transparent liquid at room temperature.

0

100

---

C

A sweet white, odorless powder solid at room temperature.

150

---

Soluble

D

A salty white crystalline solid at room

temperature.

801

1465

Soluble

E

Liquid at room temperature with strong

odor. It is the key ingredient in rubbing

alcohol.

-89

82.5

Soluble

F

A white or off-white crystalline powder. It

is usually used as flavor enhancer in cooking.

232

333.80

Soluble

Table 2: Chemical name and classification of compounds.

Sample Chemical Name of Sample Ionic or Covalent

A __ A __ B___ ___ ___ ___O___ I D ___

B __ __ __ E ___

C TABLE S __ __ A __

D S __ __ I __ M __ __ L __ __ I ___ E

E I __ O __P __ O __ Y__ __ L __O__O__

F M__ __O__O D__ __ __ __LU__A__ __ __ __

Guide Questions:

1. What type of compound has high melting point? Why?

2. What type of compound is generally insoluble in water? Why?

3. How do you determine the type of compound based on their melting point, boiling

point, and solubility?

Activity 5: Checking Ionic and Covalent Polarity

Find the electronegativity difference of the following pair of elements and

identify whether the pair of elements are likely to form an ionic or covalent

(polar/nonpolar) compounds. Write your answers on a separate answer sheet.

19


Pair of Elements Electronegativity

Value

Electronegativity

Difference

Polarity of Compound

(Ionic/ Polar or Nonpolar

Covalent)

1. Sodium

Bromine

0.9

2.8

2. Sulfur

Oxygen

2.5

3.5

3. Hydrogen

Oxygen

2.1

3.5

4. Nitrogen

Nitrogen

3.0

3.0

5. Potassium

Chlorine

0.8

3.0

6. Phosphorous

Hydrogen

2.1

2.1

7. Nitrogen

Hydrogen

3.0

2.1

8. Aluminum

Chorine

1.5

3.0

9. Carbon

Hydrogen

2.5

2.1

10. Sodium

Chlorine

0.9

3.0

Guide Questions:

1. Why do we use electronegativity to determine bond polarity?

2. What kind of elements usually form nonpolar covalent compounds?

3. What is the electronegativity difference of given pair of elements in a nonpolar

covalent compound?

4. How can you determine if a pair of elements will result in an ionic compound based

on type of elements and electronegativity difference?

5. How can you determine if a pair of elements will result in a polar covalent

compound based on type of elements and electronegativity difference?

20


Activity 6: Let’s Wrap it Up the Properties of Compounds

Complete the table below to compare the physical properties of ionic from

covalent compounds. Check the columns that correctly correspond to its physical

properties. Write your answer on a separate sheet of paper.

Physical Properties Comparative Features Ionic

Compound

Covalent

Compound

Types of Elements

metal and nonmetal

nonmetal and nonmetal

Bonding

transfer of electron(s) between

atoms

sharing of pair(s) of electron(s)

between atoms

Physical State at Room

Temperature

gas

liquid

solid

crystalline solid

Texture/Appearance

soft

hard

brittle

flexible

Melting Point

high

low

Solubility in water

high solubility

low solubility

Polarity

high polarity

low polarity

Flammability

mostly flammable

mostly nonflammable

Conductor of Heat

good conductor

poor conductor

Electrical Conductivity

(s)

Do not conduct electricity

Electrical Conductivity

(aq)

Conduct electricity

Guide Questions:

1. How do we identify the different types of compounds?

2. How can knowledge on the different properties of compounds be useful in our daily

life?

21


What I Have Learned

Supply the missing word or words to complete each statement. Write your answers on a separate sheet of paper.

1. Compounds are made up of elements that are chemically bonded by __________

forces.

2. Chemically bonded compounds can be classified into ionic or __________

compound.

3. Ionic compound is formed by complete __________ of electrons from metals to

nonmetals, thus ions are formed.

4. Covalent compound is formed when nonmetals __________ their valence electrons

with another nonmetal.

5. Like elements, compounds have __________ that allow us to identify them by just

observing at a given sample of compound.

6. At normal atmospheric pressure and temperature, __________ compounds exist

only in crystalline solids.

7. In general, __________ compounds exist as solid, liquid, or gas at normal

atmospheric pressure and temperature.

8. In a compound, polarity results in the distribution of electrical charge over the

atoms joined by the bond. Polarity of compounds depend on the __________

difference of elements involves.

9. Compounds that involves metal and nonmetal and has an electronegativity

difference of greater than __________ results in an ionic compound.

10. Compounds that involves both nonmetals and has electronegativity difference of

less than 1.9 but greater than 0.5 results in a __________ covalent. On the other

hand, two identical nonmetals always form __________ covalent like oxygen gas (𝑂2)

and nitrogen gas (𝑁2).

11. Ionic compounds tend to have __________ polarity, while covalent compounds have

__________ polarity.

12. __________ tend to be hard and brittle while __________ tend to be softer and more

flexible.

13. ___________ exist in stable crystalline structures. Therefore, they have higher

melting and boiling points compared to __________.

14. Ionic compounds are usually __________ in water, while covalent compounds tend

to be __________ in water.

15. __________ compounds tend to be more flammable than __________ compounds.

16. In a solution, __________ compounds conduct electricity, but not in solid phase.

17. __________compounds are poor conductors of electricity both in solid phase and in

solution.

18. __________, that has same chemical formula of water and __________, a type of

electrochemical cell that uses chemical reaction to produce electric current, are

some examples of natural phenomena that uses the properties of ionic and covalent

compounds

22


What I Can Do

Read each statement below that shows how compounds affect our daily life.

Underline the properties of compounds and determine the name and type of

compounds involved. Write the type of compounds (ionic/covalent) on the space

before each number, then indicate the name or example of compound inside the

box. Write your answer on a separate sheet of paper.

_________________ 1. is an electrochemical cell that uses

chemical reactions to produce electric current. A battery is an

example of voltaic cells, android phone and laptop are just few

examples of gadgets that are powered by battery.

_________________ 2. is a colorless liquid at room temperature.

It is commonly used as nail polish remover; it is also helpful

in removing sticky substances from textiles like cotton and

silk.

_________________ 3. is locally known as sukang paombong. It

is a cloudy white liquid at room temperature that has a

distinct acidic taste and yeasty flavor which are widely used

in Filipino cuisine. This vinegar was named after the town of

Paombong, Bulacan where it is a traditional industry.

_________________ 4. is a white crystalline volatile solid ball of

chemical pesticide and deodorant. It has a distinct odor and

used when storing clothing and other articles susceptible to

damage from mold or moth larvae.

_________________ 5. does not have a fixed melting point. Instead,

as this compound increases in temperature, its molecules

begins to decompose producing a more fluid product known

as caramel over a wide range of temperatures. This compound

exists also in solid at room temperature.

_________________ 6. is usually flammable and mainly used as

an engine fuel in vehicles. It is a fuel made from crude oil and

other petroleum liquids.

_________________ 7. is a compound with strong conductivity

and dissociates completely into charged atoms or ions when

dissolved in water. It is commonly used as food seasoning.

________________ 8. have chemical formula same as water. It

begins to form when an extremely cold-water droplet freezes

onto a pollen or dust particle in the sky that creates an ice

crystal.

23


_________________9. is a soft and white solid at room

temperature. It melts and burns easily. This compound is

usually used to make candles.

________________ 10. is a compound that has a bitter, salty

taste. At room temperature, it is solid and soluble in water. It

is a leavening agent used in baked goods like cakes, muffins,

and cookies.

Assessment

Read the following questions carefully. Choose the letter of the correct

answer. Write your answer on a separate sheet of paper.

1. What kind of substance is being represented by the structure below?

A. metal

B. nonmetal

C. ionic compound

D. covalent compound

2. Which of the following are the properties of covalent compounds?

I. It is soft and flexible

II. It conducts electricity in a solution

III. It does not conduct electricity both in solid phase and in a solution.

IV. It may exist as solid, liquid, or gas at normal atmospheric pressure and

temperature

A. A. I and II only C. I, II, and III only

B. B. II and III only D. I, III, and IV only

3. What is the nature of the substances described in the table?

Substances Appearance Melting Point

NaCl- sodium chloride White crystalline solid 801˚C

KCl – Potassium chloride White or colorless crystal 770˚C

MgCl2 – Magnesium chloride White or colorless crystalline

solid

1412˚C

A. They are ionic compounds and have high melting points.

B. They are ionic compounds and have low melting points.

C. They are covalent compounds and have low melting points.

D. They are covalent compounds and have high melting points.

24


4. Which of the following statements BEST explain why covalent compounds do

not conduct electricity when dissolved in water?

A. Covalent compounds have lower melting point.

B. Covalent compounds are weakly bonded.

C. Covalent compounds dissolve into molecules.

D. Covalent compounds don’t dissolve in water since they are composed of

nonpolar molecules.

5. Which of the following substances does NOT conduct electricity?

I. salt solution III. salt granules

II. sugar solution IV. monosodium glutamate solution

A. I only C. II and III only

B. I and II only D. I and IV only

6. Which of the following substances do exist in solid, liquid, or gas at room

temperature and normal atmospheric pressure?

I. gasoline II. mothballs III. salt IV. water

A. I only C. I, II, III only

B. II only D. I, II and IV only

7. Which of the following pair of elements will result in nonpolar covalent

compound?

A. Aluminum and Chlorine C. Sulfur and Oxygen

B. Phosphorous and Hydrogen D. Sodium and Chlorine

8. Which of the following compounds have low melting point?

I. salt III. paraffin wax

II. sugar IV. monosodium glutamate

A. I and II only C. I, II, and III only

B. II and III only D. II, III, and IV only

9. Which of the following compound is ionic based on their chemical formula

A. KCl C. NH3

B. HCl D. C12H22O11

25


10. Which are TRUE about snowflakes?

I. It is a covalent compound.

II. All snowflakes are six sided.

III. II. Its chemical formula is the same as water.

IV. Its structure is the same as the crystalline lattice of an ionic compound.


B. III and IV only D. I, II, and IV only

11. Most Filipino athletes consume more ions after a vigorous training by

consuming sport drinks and fruits that are rich in electrolytes to replenish lost

ions necessary for important bodily functions. Which of the following examples

of electrolytes are commonly found in sport drinks?

A. I. glucose II. sodium III. potassium IV. magnesium


B. II and III only D. II, III, and IV only

For questions no. 12-13, refer to the figure below of voltaic cell:

12. How does voltaic cell produce electricity?

A. electrochemical cell

B. oxidation reactions

C. reduction reactions

D. oxidation and reduction reactions

26


13. Which of the following is/are TRUE about voltaic cells as shown in the diagram

below?

I. The reaction that takes place in it is reversible.

II. They have two conductive electrodes, a positive and negative electrode.

III. It is a device that produces electric current from energy released by

spontaneous reduction-oxidation reaction.

A. I only B. II only C. I and II only D. II and III only

14. Which of the following shows the INCORRECT analogies using the information

you can get from the diagram?

I. anode-reduction: cathode oxidation

II. anode-oxidation: cathode reduction

III. positive electrode – anode: negative electrode - cathode

IV. positive electrode – cathode: negative electrode – anode

A. II only

B. IV only

C. I and III only

D. II and IV only

15. Maria is working as a student assistant in their school Chemistry laboratory.

Which of the following shows a direct application of knowledge about the

properties of compounds as a student assistant in the Chemistry laboratory?

I. In proper storing of different substances for safety purposes.

II. In assisting students when it comes to proper usage of substances.

III. In identifying hazardous substances through reading chemical abels.

IV. In keeping records of borrowed laboratory tools and equipment in the

laboratory.

A. I only

B. II only

C. I and II only

D. III and IV only

Additional Activities

Blockout Match!

Write I if the block shows an example, a property or natural phenomena

(that uses properties of compounds) related to ionic compound and C for covalent compound. Write your answer on a separate sheet of paper.

27


1

6

11

16 21

2

7

𝐶6𝐻22𝑂11

12

17

22

3

8

FREE

18

23

4

9

14

19

24

5

10

15 20 25

Guide Questions:

1. As a student, why is it important to know and understand the different

properties of ionic and covalent compounds?

2. For a scientist, how important is it to have a deeper understanding about the different properties of compound?

HARD

BRITTLE LOW

MELTING

POINT

HIGH

BOILING

POINT

N HIGH

MELTING

POINT

28


Answer Key

What I Know

1. A 11. C

2. B 12. C

3. B 13. D

4. D 14. D

5. D 15. A

6. D

7. C

8. B

9. D

10. A

What’s In

Group 1A- H, Li, Na, K, Rb, Cs, and Fr

Group IIA- Be, Mg, Ca, Sr, Ba, and Ra

Group IIIA- B, Al, Ga, In, and Tl

Group IVA- C, Si, Ge, Sn, Pb, and Fl

Group VA- N, P, As, Sb, and Bi

Group VIA- O. S, Se, Te, Po, and Lv

Group VIIA- F, Cl, Br, I, and At

Group VIIIA- He, Ne, Ar, Kr, Xe, and Rn

What’s New

Guide Questions:

1. A compound is form when two or more elements bond.

2. A compound contains two or more different elements.

29


What’s More

Activity 1 Out with the Old, In with the New

1. Sodium chloride is composed of metal and nonmetal, while water is

composed of both nonmetal elements.

2. Sodium chloride is formed when sodium atoms interact with chlorine

atoms by transferring its valence electron to chlorine atom. On the other

hand, water is formed when two atoms of hydrogen interact with an atom

of oxygen by sharing their valence electrons.

3.Each of the individual atoms in a compound is unstable, to attain their

stability the individual atoms transfer or share their valence electrons.

4. Sodium chloride is an ionic compound, while water is a covalent

compound.

5. Ionic compounds can be identified if the compound is formed by the

transfer of electrons between metal and non-metallic element. On the other

hand, covalent compounds involved sharing of pair(s) of electron(s) between

non-metallic element.

Activity 2 Know My Identity through My Chemical Formula

Guide Questions:

1. Ionic and covalent compound can be identified and describe using their

chemical name and formula. If the element involved in a compound name

and formula are metal and nonmetal, then the compound is ionic and if

the element involved are both nonmetals, the compound is covalent.

30


Activity 3 Who Got the Power?

Guide Questions:

1. Salt dissolve in water is the sample compounds that conduct

electricity.

2. Salt granules is in solid state. Therefore, ions are not free to move

for a charge to flow.

3. Sugar in solid state and in a solution dissolved as molecules and not

into ions. Therefore, sugar molecules cannot carry an electric charge.

4. Sugar is composed of nonmetals, therefore, it is an example of

covalent compound, while salt is composed of metals, therefore, it is

an ionic compound.

5. The type of compound that can conduct electricity is an ionic

compound.

Activity No.4 Investigating Ionic and Covalent Profile

Sample A - Carbon dioxide – Covalent

Sample B – Water – Covalent

Sample C – Table Sugar – Covalent

Sample D – Sodium Chloride – Ionic

Sample E – Isopropyl Alcohol- Covalent

Sample F – Monosodium Glutamate -Covalent

Guide Questions:

1. Ionic compound has high melting point because strong force of

attraction between oppositely charged ions. Therefore, a large amount

of heat energy is required to separate the ions.

2. Generally, covalent compound is insoluble in water. This is because

water molecules are polar, which means they are favorable to dissolve

compounds that are also polar and insoluble for nonpolar molecules.

3. Knowing the physical properties of compound will help you

determine the type of compounds that you have. In General, ionic

compound has high melting point, boiling point, and solubility

compared to covalent compound.

31


What I Can Do

Activity 5 Checking Ionic and Covalent Compound Polarity

Guide Questions:

1. Electronegativity of an atom refers on how strongly it attracts electron

to itself. Electronegativity values of the two atoms involved in a bond

affect the polarity of a bond.

2. Two nonmetals that are identical usually formed a nonpolar covalent

compound.

3. If the electronegativity difference of a compound is less than 0.4, it is

considered as nonpolar covalent.

4. If a pair of elements is composed of metal and nonmetal, and its

electronegativity difference is greater than 1.9, this compound is

considered as ionic.

5. If a pair of elements is composed of nonmetals and its electronegativity difference is less than 1.9 but greater than 0.4, this compound is

considered as polar covalent compound.

Activity 6 Let’s Wrap it Up the Properties of Compound

Guide Questions:

1. The physical properties of compounds can be used to identify the

different types of compounds.

2. Knowledge about the physical properties of compounds can help us

understand how and why certain compounds behave. It can also be used

as a guide when it comes to safety and precaution in consuming,

handling and storing compounds.

32


Activity 6 Let’s Wrapped Up the Properties of Compound

What I Have Learned

1. electrostatic force 10. polar, nonpolar

2. covalent bond 11. high, low

3. transfer 12. ionic, covalent

4. share 13. ionic, covalent

5. properties 14. soluble, insoluble

6. ionic 15. covalent, ionic

7. covalent 16. ionic

8. electronegativity 17. covalent

9. 1.9 18. snowflakes, voltaic cell

33


What I Can Do

Assessment

1. D 6. D 11. D

2. D 7. A 12. D

3. A 8. B 13. D

4. C 9. A 14. C

5. C 10. C 15. C

Additional Activities

Guide Questions:

1. As a student knowing and understanding the different properties of

ionic and covalent compounds can serve as a guide when it comes in

using and consuming certain substance.

2. Deeper understanding of the different properties of compounds help

scientist to create more desirable products by manipulating certain

properties of compounds.

34


References

Book

Alvarez, Liza A., Dave G. Angeles, Hernan L. Apurada, Ma. Pilar P. Carmona, Oliver

A. Lahorra, Judith F. Marcaida, Ma. Regaele A. Olarte, Estrella C. Osorio, Digna C. Paningbatan, Marivic S. Rosales, and Ma. Teresa B. Delos Santos. Science - Grade 9

Learner’s Module. Pasig City: Department of Education, 2014, 50-71.

Website

Mott, Vallerie. “Introduction to Chemistry.” Lumen. Accessed August 3, 2020.

https://courses.lumenlearning.com/introchem/chapter/comparison-between-

covalent-and-ionic-compounds/.

Others

Agulto, Jocelyn R., 2nd Quarter: Science Progressive Formative Assessment Grade 9:

Chemistry-Matter, Tugatog National High School, SDO-Malabon City, 2019.

https://courses.lumenlearning.com/introchem/chapter/comparison-between-covalent-and-ionic-compounds/

https://courses.lumenlearning.com/introchem/chapter/comparison-between-covalent-and-ionic-compounds/

For inquiries or feedback, please write or call:

Department of Education - Bureau of Learning Resources (DepEd-BLR)

Ground Floor, Bonifacio Bldg., DepEd Complex

Meralco Avenue, Pasig City, Philippines 1600

Telefax: (632) 8634-1072; 8634-1054; 8631-4985

Email Address: [email protected] * [email protected]

Science Quarter 2- Matter - DepEd Tambayan

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